Unless otherwise indicated herein, the approaches described in this section are not prior art to the claims in this disclosure and are not admitted to be prior art by inclusion in this section.
Network availability is a critical metric for service providers as it has a direct bearing on their profitability. Outages translate not only to lost revenue but also to potential penalties mandated by contractual agreements with customers running mission-critical applications that require tight Service Level Agreements (SLAs). This is true for any carrier network, and networks employing Layer2 Virtual Private Network (L2VPN) technology are no exception. Network high-availability can be achieved by employing intra and inter-chassis redundancy mechanisms. The inter-chassis redundancy mechanism allows set of two or more peers forming an inter-chassis device.
An inter-chassis device appears to be a logical device but actually consists of several physical devices to form a redundancy group. All the devices in the inter-chassis device are configured as peers to others. Peers in the inter-chassis device could be directly connected or indirectly connected.
Referring to FIG. 1, the left portion illustrates the physical view of an inter-chassis device, while the right portion illustrates the logical view of the inter-chassis device. As shown in FIG. 1, both Node A and Node B are connected physically to Node D. In logical, the two nodes act as one node to Node D, i.e., Node AB, as shown in right side of FIG. 1.
When deployed under Intermediate system-Intermediate system (IS-IS) protocol, the inter-chassis device (for example, Node AB) appears as one Intermediate System in the topology. Node A and Node B (referred as Peer A and Peer B hereunder) are peers to each other in Node AB.
There is no automatic discovery mechanism for peers in an inter-chassis device under IS-IS environment. The peers' addresses are manually configured.